Speaking as someone who almost quit after game 1 about a year and a half ago due to the following things:
-Perceived, glaring difference between low and high levels
-Perceived ineffectiveness in any meaningful situation, accompanied by a perceived inability to ever be a factor
-The 'cannon-fodder' nature of monstering
-Perceived lack of IP motivations of other characters
I have to say that, as it stands, it takes a good deal of perseverance to stick to the game as a newbie in the current system. I've taken this in stride and have learned to make my own fun, made easier by much more accessible staff. The solution to retaining newbies, in my opinion, is multi-tiered.
The most important thing is to make sure that someone wants to keep the player around - I'm not likely to go where I am not wanted, so even if I understand that I am not wanted IP, it should be made clear (perhaps after game, or that scene in a quick aside) that it's an IP reaction. Some people haven't developed the fine sense of IP/OOP division that experienced players have (and still sometimes miss). I almost didn't return after my first game, and if not for a few folks making me feel wanted, I would certainly have not returned at all.
Another important thing to remember is that some people are not as patient as others. I recognize and understand that a player who starts at level 1.5 and is now currently level 85 definitely should be commended for his outstanding loyalty, but there should be mechanisms in place to make that particular carrot just a bit closer.
There is something to be said for intangilble rewards. I play one of those good guys - in fact, just about everything my character has is a pure gift. I have to be reminded to search the few kills I do get sometimes. My character cares about gold only insomuch as it will help him get something he needs to help those he sees as friends. [Ask the Healers' Guild about how much my character spends on potions.] Should characters like myself be left out of the loop and relatively underpowered because we are not greedy?
Why did I stay? 1) Partial fulfillment of character vision - I actually achieved the class I was shooting for. 2) Ongoing plots, both with and without Storyteller/Plot moderation 3) Feeling welcome to come back. These things keep me coming back and having fun and sustained me after almost quitting. I even tried to cap a couple of times, but I didn't understand the rules, and threw away money (hard enough for me to get as it is) to do so.
It's all well and good to say that those new players who want to grind levels faster should work for the game, but it defeats the purpose, somewhat, if they spend all their low levels working for the game. I have heard the suggestion given to newer players many times to mostly monster their first events - to get a handle on the system (which is a good reason, in my opinion) and to power their characters (which is only semi-good, again - my opinion). As a new player, I would want the experience of playing my character and getting a feel for the game in that context - and not being punished for wanting that experience. New players (and mid-levels, the forgotten demographic in my opinion) should see noticeable improvement without having to jump through hoops. One of the aforementioned EEP systems, combined with EEP chits, would go a long way toward that.
It's hard to balance, but the closer we come to that balance, the better the game will be as a whole.
Something that would concern me about EEP chits is that not every character will stoop to loot a corpse IP - I think that they should be handed out at the end of a module/planned encounter by staff, but kept to a minimum on roaming MT monsters. This way, if you want the big EEPs, you won't be inclined to monster-bash, but instead seek out opportunities for greater adventure. Having some MT encounters reward for roleplaying would also help, but this would have to be carefully moderated for abuse.